package org.bouncycastle.jce.provider;

import java.util.Collection;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

import org.bouncycastle.asn1.ASN1OctetString;
import org.bouncycastle.asn1.ASN1Sequence;
import org.bouncycastle.asn1.DERIA5String;
import org.bouncycastle.asn1.x509.GeneralName;
import org.bouncycastle.asn1.x509.GeneralSubtree;
import org.bouncycastle.util.Arrays;
import org.bouncycastle.util.Strings;

@SuppressWarnings({ "rawtypes", "unchecked" })
public class PKIXNameConstraintValidator {
    private Set excludedSubtreesDN = new HashSet();

    private Set excludedSubtreesDNS = new HashSet();

    private Set excludedSubtreesEmail = new HashSet();

    private Set excludedSubtreesURI = new HashSet();

    private Set excludedSubtreesIP = new HashSet();

    private Set permittedSubtreesDN;

    private Set permittedSubtreesDNS;

    private Set permittedSubtreesEmail;

    private Set permittedSubtreesURI;

    private Set permittedSubtreesIP;

    public PKIXNameConstraintValidator() {
    }

    private static boolean withinDNSubtree(ASN1Sequence dns,
            ASN1Sequence subtree) {
        if (subtree.size() < 1) {
            return false;
        }

        if (subtree.size() > dns.size()) {
            return false;
        }

        for (int j = subtree.size() - 1; j >= 0; j--) {
            if (!subtree.getObjectAt(j).equals(dns.getObjectAt(j))) {
                return false;
            }
        }

        return true;
    }

    public void checkPermittedDN(ASN1Sequence dns)
            throws PKIXNameConstraintValidatorException {
        checkPermittedDN(permittedSubtreesDN, dns);
    }

    public void checkExcludedDN(ASN1Sequence dns)
            throws PKIXNameConstraintValidatorException {
        checkExcludedDN(excludedSubtreesDN, dns);
    }

    private void checkPermittedDN(Set permitted, ASN1Sequence dns)
            throws PKIXNameConstraintValidatorException {
        if (permitted == null) {
            return;
        }

        if (permitted.isEmpty() && dns.size() == 0) {
            return;
        }
        Iterator it = permitted.iterator();

        while (it.hasNext()) {
            ASN1Sequence subtree = (ASN1Sequence) it.next();

            if (withinDNSubtree(dns, subtree)) {
                return;
            }
        }

        throw new PKIXNameConstraintValidatorException(
                "Subject distinguished name is not from a permitted subtree");
    }

    private void checkExcludedDN(Set excluded, ASN1Sequence dns)
            throws PKIXNameConstraintValidatorException {
        if (excluded.isEmpty()) {
            return;
        }

        Iterator it = excluded.iterator();

        while (it.hasNext()) {
            ASN1Sequence subtree = (ASN1Sequence) it.next();

            if (withinDNSubtree(dns, subtree)) {
                throw new PKIXNameConstraintValidatorException(
                        "Subject distinguished name is from an excluded subtree");
            }
        }
    }

    private Set intersectDN(Set permitted, Set dns) {
        Set intersect = new HashSet();
        for (Iterator it = dns.iterator(); it.hasNext();) {
            ASN1Sequence dn = ASN1Sequence.getInstance(((GeneralSubtree) it
                    .next()).getBase().getName().getDERObject());
            if (permitted == null) {
                if (dn != null) {
                    intersect.add(dn);
                }
            } else {
                Iterator _iter = permitted.iterator();
                while (_iter.hasNext()) {
                    ASN1Sequence subtree = (ASN1Sequence) _iter.next();

                    if (withinDNSubtree(dn, subtree)) {
                        intersect.add(dn);
                    } else if (withinDNSubtree(subtree, dn)) {
                        intersect.add(subtree);
                    }
                }
            }
        }
        return intersect;
    }

    private Set unionDN(Set excluded, ASN1Sequence dn) {
        if (excluded.isEmpty()) {
            if (dn == null) {
                return excluded;
            }
            excluded.add(dn);

            return excluded;
        } else {
            Set intersect = new HashSet();

            Iterator it = excluded.iterator();
            while (it.hasNext()) {
                ASN1Sequence subtree = (ASN1Sequence) it.next();

                if (withinDNSubtree(dn, subtree)) {
                    intersect.add(subtree);
                } else if (withinDNSubtree(subtree, dn)) {
                    intersect.add(dn);
                } else {
                    intersect.add(subtree);
                    intersect.add(dn);
                }
            }

            return intersect;
        }
    }

    private Set intersectEmail(Set permitted, Set emails) {
        Set intersect = new HashSet();
        for (Iterator it = emails.iterator(); it.hasNext();) {
            String email = extractNameAsString(((GeneralSubtree) it.next())
                    .getBase());

            if (permitted == null) {
                if (email != null) {
                    intersect.add(email);
                }
            } else {
                Iterator it2 = permitted.iterator();
                while (it2.hasNext()) {
                    String _permitted = (String) it2.next();

                    intersectEmail(email, _permitted, intersect);
                }
            }
        }
        return intersect;
    }

    private Set unionEmail(Set excluded, String email) {
        if (excluded.isEmpty()) {
            if (email == null) {
                return excluded;
            }
            excluded.add(email);
            return excluded;
        } else {
            Set union = new HashSet();

            Iterator it = excluded.iterator();
            while (it.hasNext()) {
                String _excluded = (String) it.next();

                unionEmail(_excluded, email, union);
            }

            return union;
        }
    }

    /**
     * Returns the intersection of the permitted IP ranges in
     * <code>permitted</code> with <code>ip</code>.
     * 
     * @param permitted
     *            A <code>Set</code> of permitted IP addresses with their subnet
     *            mask as byte arrays.
     * @param ips
     *            The IP address with its subnet mask.
     * @return The <code>Set</code> of permitted IP ranges intersected with
     *         <code>ip</code>.
     */
    private Set intersectIP(Set permitted, Set ips) {
        Set intersect = new HashSet();
        for (Iterator it = ips.iterator(); it.hasNext();) {
            byte[] ip = ASN1OctetString.getInstance(
                    ((GeneralSubtree) it.next()).getBase().getName())
                    .getOctets();
            if (permitted == null) {
                if (ip != null) {
                    intersect.add(ip);
                }
            } else {
                Iterator it2 = permitted.iterator();
                while (it2.hasNext()) {
                    byte[] _permitted = (byte[]) it2.next();
                    intersect.addAll(intersectIPRange(_permitted, ip));
                }
            }
        }
        return intersect;
    }

    /**
     * Returns the union of the excluded IP ranges in <code>excluded</code> with
     * <code>ip</code>.
     * 
     * @param excluded
     *            A <code>Set</code> of excluded IP addresses with their subnet
     *            mask as byte arrays.
     * @param ip
     *            The IP address with its subnet mask.
     * @return The <code>Set</code> of excluded IP ranges unified with
     *         <code>ip</code> as byte arrays.
     */
    private Set unionIP(Set excluded, byte[] ip) {
        if (excluded.isEmpty()) {
            if (ip == null) {
                return excluded;
            }
            excluded.add(ip);

            return excluded;
        } else {
            Set union = new HashSet();

            Iterator it = excluded.iterator();
            while (it.hasNext()) {
                byte[] _excluded = (byte[]) it.next();
                union.addAll(unionIPRange(_excluded, ip));
            }

            return union;
        }
    }

    /**
     * Calculates the union if two IP ranges.
     * 
     * @param ipWithSubmask1
     *            The first IP address with its subnet mask.
     * @param ipWithSubmask2
     *            The second IP address with its subnet mask.
     * @return A <code>Set</code> with the union of both addresses.
     */
    private Set unionIPRange(byte[] ipWithSubmask1, byte[] ipWithSubmask2) {
        Set set = new HashSet();

        // difficult, adding always all IPs is not wrong
        if (Arrays.areEqual(ipWithSubmask1, ipWithSubmask2)) {
            set.add(ipWithSubmask1);
        } else {
            set.add(ipWithSubmask1);
            set.add(ipWithSubmask2);
        }
        return set;
    }

    /**
     * Calculates the interesction if two IP ranges.
     * 
     * @param ipWithSubmask1
     *            The first IP address with its subnet mask.
     * @param ipWithSubmask2
     *            The second IP address with its subnet mask.
     * @return A <code>Set</code> with the single IP address with its subnet
     *         mask as a byte array or an empty <code>Set</code>.
     */
    private Set intersectIPRange(byte[] ipWithSubmask1, byte[] ipWithSubmask2) {
        if (ipWithSubmask1.length != ipWithSubmask2.length) {
            return Collections.EMPTY_SET;
        }
        byte[][] temp = extractIPsAndSubnetMasks(ipWithSubmask1, ipWithSubmask2);
        byte ip1[] = temp[0];
        byte subnetmask1[] = temp[1];
        byte ip2[] = temp[2];
        byte subnetmask2[] = temp[3];

        byte minMax[][] = minMaxIPs(ip1, subnetmask1, ip2, subnetmask2);
        byte[] min;
        byte[] max;
        max = min(minMax[1], minMax[3]);
        min = max(minMax[0], minMax[2]);

        // minimum IP address must be bigger than max
        if (compareTo(min, max) == 1) {
            return Collections.EMPTY_SET;
        }
        // OR keeps all significant bits
        byte[] ip = or(minMax[0], minMax[2]);
        byte[] subnetmask = or(subnetmask1, subnetmask2);
        return Collections.singleton(ipWithSubnetMask(ip, subnetmask));
    }

    /**
     * Concatenates the IP address with its subnet mask.
     * 
     * @param ip
     *            The IP address.
     * @param subnetMask
     *            Its subnet mask.
     * @return The concatenated IP address with its subnet mask.
     */
    private byte[] ipWithSubnetMask(byte[] ip, byte[] subnetMask) {
        int ipLength = ip.length;
        byte[] temp = new byte[ipLength * 2];
        System.arraycopy(ip, 0, temp, 0, ipLength);
        System.arraycopy(subnetMask, 0, temp, ipLength, ipLength);
        return temp;
    }

    /**
     * Splits the IP addresses and their subnet mask.
     * 
     * @param ipWithSubmask1
     *            The first IP address with the subnet mask.
     * @param ipWithSubmask2
     *            The second IP address with the subnet mask.
     * @return An array with two elements. Each element contains the IP address
     *         and the subnet mask in this order.
     */
    private byte[][] extractIPsAndSubnetMasks(byte[] ipWithSubmask1,
            byte[] ipWithSubmask2) {
        int ipLength = ipWithSubmask1.length / 2;
        byte ip1[] = new byte[ipLength];
        byte subnetmask1[] = new byte[ipLength];
        System.arraycopy(ipWithSubmask1, 0, ip1, 0, ipLength);
        System.arraycopy(ipWithSubmask1, ipLength, subnetmask1, 0, ipLength);

        byte ip2[] = new byte[ipLength];
        byte subnetmask2[] = new byte[ipLength];
        System.arraycopy(ipWithSubmask2, 0, ip2, 0, ipLength);
        System.arraycopy(ipWithSubmask2, ipLength, subnetmask2, 0, ipLength);
        return new byte[][] { ip1, subnetmask1, ip2, subnetmask2 };
    }

    /**
     * Based on the two IP addresses and their subnet masks the IP range is
     * computed for each IP address - subnet mask pair and returned as the
     * minimum IP address and the maximum address of the range.
     * 
     * @param ip1
     *            The first IP address.
     * @param subnetmask1
     *            The subnet mask of the first IP address.
     * @param ip2
     *            The second IP address.
     * @param subnetmask2
     *            The subnet mask of the second IP address.
     * @return A array with two elements. The first/second element contains the
     *         min and max IP address of the first/second IP address and its
     *         subnet mask.
     */
    private byte[][] minMaxIPs(byte[] ip1, byte[] subnetmask1, byte[] ip2,
            byte[] subnetmask2) {
        int ipLength = ip1.length;
        byte[] min1 = new byte[ipLength];
        byte[] max1 = new byte[ipLength];

        byte[] min2 = new byte[ipLength];
        byte[] max2 = new byte[ipLength];

        for (int i = 0; i < ipLength; i++) {
            min1[i] = (byte) (ip1[i] & subnetmask1[i]);
            max1[i] = (byte) (ip1[i] & subnetmask1[i] | ~subnetmask1[i]);

            min2[i] = (byte) (ip2[i] & subnetmask2[i]);
            max2[i] = (byte) (ip2[i] & subnetmask2[i] | ~subnetmask2[i]);
        }

        return new byte[][] { min1, max1, min2, max2 };
    }

    private void checkPermittedEmail(Set permitted, String email)
            throws PKIXNameConstraintValidatorException {
        if (permitted == null) {
            return;
        }

        Iterator it = permitted.iterator();

        while (it.hasNext()) {
            String str = ((String) it.next());

            if (emailIsConstrained(email, str)) {
                return;
            }
        }

        if (email.length() == 0 && permitted.size() == 0) {
            return;
        }

        throw new PKIXNameConstraintValidatorException(
                "Subject email address is not from a permitted subtree.");
    }

    private void checkExcludedEmail(Set excluded, String email)
            throws PKIXNameConstraintValidatorException {
        if (excluded.isEmpty()) {
            return;
        }

        Iterator it = excluded.iterator();

        while (it.hasNext()) {
            String str = (String) it.next();

            if (emailIsConstrained(email, str)) {
                throw new PKIXNameConstraintValidatorException(
                        "Email address is from an excluded subtree.");
            }
        }
    }

    /**
     * Checks if the IP <code>ip</code> is included in the permitted set
     * <code>permitted</code>.
     * 
     * @param permitted
     *            A <code>Set</code> of permitted IP addresses with their subnet
     *            mask as byte arrays.
     * @param ip
     *            The IP address.
     * @throws PKIXNameConstraintValidatorException
     *             if the IP is not permitted.
     */
    private void checkPermittedIP(Set permitted, byte[] ip)
            throws PKIXNameConstraintValidatorException {
        if (permitted == null) {
            return;
        }

        Iterator it = permitted.iterator();

        while (it.hasNext()) {
            byte[] ipWithSubnet = (byte[]) it.next();

            if (isIPConstrained(ip, ipWithSubnet)) {
                return;
            }
        }
        if (ip.length == 0 && permitted.size() == 0) {
            return;
        }
        throw new PKIXNameConstraintValidatorException(
                "IP is not from a permitted subtree.");
    }

    /**
     * Checks if the IP <code>ip</code> is included in the excluded set
     * <code>excluded</code>.
     * 
     * @param excluded
     *            A <code>Set</code> of excluded IP addresses with their subnet
     *            mask as byte arrays.
     * @param ip
     *            The IP address.
     * @throws PKIXNameConstraintValidatorException
     *             if the IP is excluded.
     */
    private void checkExcludedIP(Set excluded, byte[] ip)
            throws PKIXNameConstraintValidatorException {
        if (excluded.isEmpty()) {
            return;
        }

        Iterator it = excluded.iterator();

        while (it.hasNext()) {
            byte[] ipWithSubnet = (byte[]) it.next();

            if (isIPConstrained(ip, ipWithSubnet)) {
                throw new PKIXNameConstraintValidatorException(
                        "IP is from an excluded subtree.");
            }
        }
    }

    /**
     * Checks if the IP address <code>ip</code> is constrained by
     * <code>constraint</code>.
     * 
     * @param ip
     *            The IP address.
     * @param constraint
     *            The constraint. This is an IP address concatenated with its
     *            subnetmask.
     * @return <code>true</code> if constrained, <code>false</code> otherwise.
     */
    private boolean isIPConstrained(byte ip[], byte[] constraint) {
        int ipLength = ip.length;

        if (ipLength != (constraint.length / 2)) {
            return false;
        }

        byte[] subnetMask = new byte[ipLength];
        System.arraycopy(constraint, ipLength, subnetMask, 0, ipLength);

        byte[] permittedSubnetAddress = new byte[ipLength];

        byte[] ipSubnetAddress = new byte[ipLength];

        // the resulting IP address by applying the subnet mask
        for (int i = 0; i < ipLength; i++) {
            permittedSubnetAddress[i] = (byte) (constraint[i] & subnetMask[i]);
            ipSubnetAddress[i] = (byte) (ip[i] & subnetMask[i]);
        }

        return Arrays.areEqual(permittedSubnetAddress, ipSubnetAddress);
    }

    private boolean emailIsConstrained(String email, String constraint) {
        String sub = email.substring(email.indexOf('@') + 1);
        // a particular mailbox
        if (constraint.indexOf('@') != -1) {
            if (email.equalsIgnoreCase(constraint)) {
                return true;
            }
        }
        // on particular host
        else if (!(constraint.charAt(0) == '.')) {
            if (sub.equalsIgnoreCase(constraint)) {
                return true;
            }
        }
        // address in sub domain
        else if (withinDomain(sub, constraint)) {
            return true;
        }
        return false;
    }

    private boolean withinDomain(String testDomain, String domain) {
        String tempDomain = domain;
        if (tempDomain.startsWith(".")) {
            tempDomain = tempDomain.substring(1);
        }
        String[] domainParts = Strings.split(tempDomain, '.');
        String[] testDomainParts = Strings.split(testDomain, '.');
        // must have at least one subdomain
        if (testDomainParts.length <= domainParts.length) {
            return false;
        }
        int d = testDomainParts.length - domainParts.length;
        for (int i = -1; i < domainParts.length; i++) {
            if (i == -1) {
                if (testDomainParts[i + d].equals("")) {
                    return false;
                }
            } else if (!domainParts[i].equalsIgnoreCase(testDomainParts[i + d])) {
                return false;
            }
        }
        return true;
    }

    private void checkPermittedDNS(Set permitted, String dns)
            throws PKIXNameConstraintValidatorException {
        if (permitted == null) {
            return;
        }

        Iterator it = permitted.iterator();

        while (it.hasNext()) {
            String str = ((String) it.next());

            // is sub domain
            if (withinDomain(dns, str) || dns.equalsIgnoreCase(str)) {
                return;
            }
        }
        if (dns.length() == 0 && permitted.size() == 0) {
            return;
        }
        throw new PKIXNameConstraintValidatorException(
                "DNS is not from a permitted subtree.");
    }

    private void checkExcludedDNS(Set excluded, String dns)
            throws PKIXNameConstraintValidatorException {
        if (excluded.isEmpty()) {
            return;
        }

        Iterator it = excluded.iterator();

        while (it.hasNext()) {
            String str = ((String) it.next());

            // is sub domain or the same
            if (withinDomain(dns, str) || dns.equalsIgnoreCase(str)) {
                throw new PKIXNameConstraintValidatorException(
                        "DNS is from an excluded subtree.");
            }
        }
    }

    /**
     * The common part of <code>email1</code> and <code>email2</code> is added
     * to the union <code>union</code>. If <code>email1</code> and
     * <code>email2</code> have nothing in common they are added both.
     * 
     * @param email1
     *            Email address constraint 1.
     * @param email2
     *            Email address constraint 2.
     * @param union
     *            The union.
     */
    private void unionEmail(String email1, String email2, Set union) {
        // email1 is a particular address
        if (email1.indexOf('@') != -1) {
            String _sub = email1.substring(email1.indexOf('@') + 1);
            // both are a particular mailbox
            if (email2.indexOf('@') != -1) {
                if (email1.equalsIgnoreCase(email2)) {
                    union.add(email1);
                } else {
                    union.add(email1);
                    union.add(email2);
                }
            }
            // email2 specifies a domain
            else if (email2.startsWith(".")) {
                if (withinDomain(_sub, email2)) {
                    union.add(email2);
                } else {
                    union.add(email1);
                    union.add(email2);
                }
            }
            // email2 specifies a particular host
            else {
                if (_sub.equalsIgnoreCase(email2)) {
                    union.add(email2);
                } else {
                    union.add(email1);
                    union.add(email2);
                }
            }
        }
        // email1 specifies a domain
        else if (email1.startsWith(".")) {
            if (email2.indexOf('@') != -1) {
                String _sub = email2.substring(email1.indexOf('@') + 1);
                if (withinDomain(_sub, email1)) {
                    union.add(email1);
                } else {
                    union.add(email1);
                    union.add(email2);
                }
            }
            // email2 specifies a domain
            else if (email2.startsWith(".")) {
                if (withinDomain(email1, email2)
                        || email1.equalsIgnoreCase(email2)) {
                    union.add(email2);
                } else if (withinDomain(email2, email1)) {
                    union.add(email1);
                } else {
                    union.add(email1);
                    union.add(email2);
                }
            } else {
                if (withinDomain(email2, email1)) {
                    union.add(email1);
                } else {
                    union.add(email1);
                    union.add(email2);
                }
            }
        }
        // email specifies a host
        else {
            if (email2.indexOf('@') != -1) {
                String _sub = email2.substring(email1.indexOf('@') + 1);
                if (_sub.equalsIgnoreCase(email1)) {
                    union.add(email1);
                } else {
                    union.add(email1);
                    union.add(email2);
                }
            }
            // email2 specifies a domain
            else if (email2.startsWith(".")) {
                if (withinDomain(email1, email2)) {
                    union.add(email2);
                } else {
                    union.add(email1);
                    union.add(email2);
                }
            }
            // email2 specifies a particular host
            else {
                if (email1.equalsIgnoreCase(email2)) {
                    union.add(email1);
                } else {
                    union.add(email1);
                    union.add(email2);
                }
            }
        }
    }

    private void unionURI(String email1, String email2, Set union) {
        // email1 is a particular address
        if (email1.indexOf('@') != -1) {
            String _sub = email1.substring(email1.indexOf('@') + 1);
            // both are a particular mailbox
            if (email2.indexOf('@') != -1) {
                if (email1.equalsIgnoreCase(email2)) {
                    union.add(email1);
                } else {
                    union.add(email1);
                    union.add(email2);
                }
            }
            // email2 specifies a domain
            else if (email2.startsWith(".")) {
                if (withinDomain(_sub, email2)) {
                    union.add(email2);
                } else {
                    union.add(email1);
                    union.add(email2);
                }
            }
            // email2 specifies a particular host
            else {
                if (_sub.equalsIgnoreCase(email2)) {
                    union.add(email2);
                } else {
                    union.add(email1);
                    union.add(email2);
                }
            }
        }
        // email1 specifies a domain
        else if (email1.startsWith(".")) {
            if (email2.indexOf('@') != -1) {
                String _sub = email2.substring(email1.indexOf('@') + 1);
                if (withinDomain(_sub, email1)) {
                    union.add(email1);
                } else {
                    union.add(email1);
                    union.add(email2);
                }
            }
            // email2 specifies a domain
            else if (email2.startsWith(".")) {
                if (withinDomain(email1, email2)
                        || email1.equalsIgnoreCase(email2)) {
                    union.add(email2);
                } else if (withinDomain(email2, email1)) {
                    union.add(email1);
                } else {
                    union.add(email1);
                    union.add(email2);
                }
            } else {
                if (withinDomain(email2, email1)) {
                    union.add(email1);
                } else {
                    union.add(email1);
                    union.add(email2);
                }
            }
        }
        // email specifies a host
        else {
            if (email2.indexOf('@') != -1) {
                String _sub = email2.substring(email1.indexOf('@') + 1);
                if (_sub.equalsIgnoreCase(email1)) {
                    union.add(email1);
                } else {
                    union.add(email1);
                    union.add(email2);
                }
            }
            // email2 specifies a domain
            else if (email2.startsWith(".")) {
                if (withinDomain(email1, email2)) {
                    union.add(email2);
                } else {
                    union.add(email1);
                    union.add(email2);
                }
            }
            // email2 specifies a particular host
            else {
                if (email1.equalsIgnoreCase(email2)) {
                    union.add(email1);
                } else {
                    union.add(email1);
                    union.add(email2);
                }
            }
        }
    }

    private Set intersectDNS(Set permitted, Set dnss) {
        Set intersect = new HashSet();
        for (Iterator it = dnss.iterator(); it.hasNext();) {
            String dns = extractNameAsString(((GeneralSubtree) it.next())
                    .getBase());
            if (permitted == null) {
                if (dns != null) {
                    intersect.add(dns);
                }
            } else {
                Iterator _iter = permitted.iterator();
                while (_iter.hasNext()) {
                    String _permitted = (String) _iter.next();

                    if (withinDomain(_permitted, dns)) {
                        intersect.add(_permitted);
                    } else if (withinDomain(dns, _permitted)) {
                        intersect.add(dns);
                    }
                }
            }
        }

        return intersect;
    }

    protected Set unionDNS(Set excluded, String dns) {
        if (excluded.isEmpty()) {
            if (dns == null) {
                return excluded;
            }
            excluded.add(dns);

            return excluded;
        } else {
            Set union = new HashSet();

            Iterator _iter = excluded.iterator();
            while (_iter.hasNext()) {
                String _permitted = (String) _iter.next();

                if (withinDomain(_permitted, dns)) {
                    union.add(dns);
                } else if (withinDomain(dns, _permitted)) {
                    union.add(_permitted);
                } else {
                    union.add(_permitted);
                    union.add(dns);
                }
            }

            return union;
        }
    }

    /**
     * The most restricting part from <code>email1</code> and
     * <code>email2</code> is added to the intersection <code>intersect</code>.
     * 
     * @param email1
     *            Email address constraint 1.
     * @param email2
     *            Email address constraint 2.
     * @param intersect
     *            The intersection.
     */
    private void intersectEmail(String email1, String email2, Set intersect) {
        // email1 is a particular address
        if (email1.indexOf('@') != -1) {
            String _sub = email1.substring(email1.indexOf('@') + 1);
            // both are a particular mailbox
            if (email2.indexOf('@') != -1) {
                if (email1.equalsIgnoreCase(email2)) {
                    intersect.add(email1);
                }
            }
            // email2 specifies a domain
            else if (email2.startsWith(".")) {
                if (withinDomain(_sub, email2)) {
                    intersect.add(email1);
                }
            }
            // email2 specifies a particular host
            else {
                if (_sub.equalsIgnoreCase(email2)) {
                    intersect.add(email1);
                }
            }
        }
        // email specifies a domain
        else if (email1.startsWith(".")) {
            if (email2.indexOf('@') != -1) {
                String _sub = email2.substring(email1.indexOf('@') + 1);
                if (withinDomain(_sub, email1)) {
                    intersect.add(email2);
                }
            }
            // email2 specifies a domain
            else if (email2.startsWith(".")) {
                if (withinDomain(email1, email2)
                        || email1.equalsIgnoreCase(email2)) {
                    intersect.add(email1);
                } else if (withinDomain(email2, email1)) {
                    intersect.add(email2);
                }
            } else {
                if (withinDomain(email2, email1)) {
                    intersect.add(email2);
                }
            }
        }
        // email1 specifies a host
        else {
            if (email2.indexOf('@') != -1) {
                String _sub = email2.substring(email2.indexOf('@') + 1);
                if (_sub.equalsIgnoreCase(email1)) {
                    intersect.add(email2);
                }
            }
            // email2 specifies a domain
            else if (email2.startsWith(".")) {
                if (withinDomain(email1, email2)) {
                    intersect.add(email1);
                }
            }
            // email2 specifies a particular host
            else {
                if (email1.equalsIgnoreCase(email2)) {
                    intersect.add(email1);
                }
            }
        }
    }

    private void checkExcludedURI(Set excluded, String uri)
            throws PKIXNameConstraintValidatorException {
        if (excluded.isEmpty()) {
            return;
        }

        Iterator it = excluded.iterator();

        while (it.hasNext()) {
            String str = ((String) it.next());

            if (isUriConstrained(uri, str)) {
                throw new PKIXNameConstraintValidatorException(
                        "URI is from an excluded subtree.");
            }
        }
    }

    private Set intersectURI(Set permitted, Set uris) {
        Set intersect = new HashSet();
        for (Iterator it = uris.iterator(); it.hasNext();) {
            String uri = extractNameAsString(((GeneralSubtree) it.next())
                    .getBase());
            if (permitted == null) {
                if (uri != null) {
                    intersect.add(uri);
                }
            } else {
                Iterator _iter = permitted.iterator();
                while (_iter.hasNext()) {
                    String _permitted = (String) _iter.next();
                    intersectURI(_permitted, uri, intersect);
                }
            }
        }
        return intersect;
    }

    private Set unionURI(Set excluded, String uri) {
        if (excluded.isEmpty()) {
            if (uri == null) {
                return excluded;
            }
            excluded.add(uri);

            return excluded;
        } else {
            Set union = new HashSet();

            Iterator _iter = excluded.iterator();
            while (_iter.hasNext()) {
                String _excluded = (String) _iter.next();

                unionURI(_excluded, uri, union);
            }

            return union;
        }
    }

    private void intersectURI(String email1, String email2, Set intersect) {
        // email1 is a particular address
        if (email1.indexOf('@') != -1) {
            String _sub = email1.substring(email1.indexOf('@') + 1);
            // both are a particular mailbox
            if (email2.indexOf('@') != -1) {
                if (email1.equalsIgnoreCase(email2)) {
                    intersect.add(email1);
                }
            }
            // email2 specifies a domain
            else if (email2.startsWith(".")) {
                if (withinDomain(_sub, email2)) {
                    intersect.add(email1);
                }
            }
            // email2 specifies a particular host
            else {
                if (_sub.equalsIgnoreCase(email2)) {
                    intersect.add(email1);
                }
            }
        }
        // email specifies a domain
        else if (email1.startsWith(".")) {
            if (email2.indexOf('@') != -1) {
                String _sub = email2.substring(email1.indexOf('@') + 1);
                if (withinDomain(_sub, email1)) {
                    intersect.add(email2);
                }
            }
            // email2 specifies a domain
            else if (email2.startsWith(".")) {
                if (withinDomain(email1, email2)
                        || email1.equalsIgnoreCase(email2)) {
                    intersect.add(email1);
                } else if (withinDomain(email2, email1)) {
                    intersect.add(email2);
                }
            } else {
                if (withinDomain(email2, email1)) {
                    intersect.add(email2);
                }
            }
        }
        // email1 specifies a host
        else {
            if (email2.indexOf('@') != -1) {
                String _sub = email2.substring(email2.indexOf('@') + 1);
                if (_sub.equalsIgnoreCase(email1)) {
                    intersect.add(email2);
                }
            }
            // email2 specifies a domain
            else if (email2.startsWith(".")) {
                if (withinDomain(email1, email2)) {
                    intersect.add(email1);
                }
            }
            // email2 specifies a particular host
            else {
                if (email1.equalsIgnoreCase(email2)) {
                    intersect.add(email1);
                }
            }
        }
    }

    private void checkPermittedURI(Set permitted, String uri)
            throws PKIXNameConstraintValidatorException {
        if (permitted == null) {
            return;
        }

        Iterator it = permitted.iterator();

        while (it.hasNext()) {
            String str = ((String) it.next());

            if (isUriConstrained(uri, str)) {
                return;
            }
        }
        if (uri.length() == 0 && permitted.size() == 0) {
            return;
        }
        throw new PKIXNameConstraintValidatorException(
                "URI is not from a permitted subtree.");
    }

    private boolean isUriConstrained(String uri, String constraint) {
        String host = extractHostFromURL(uri);
        // a host
        if (!constraint.startsWith(".")) {
            if (host.equalsIgnoreCase(constraint)) {
                return true;
            }
        }

        // in sub domain or domain
        else if (withinDomain(host, constraint)) {
            return true;
        }

        return false;
    }

    private static String extractHostFromURL(String url) {
        // see RFC 1738
        // remove ':' after protocol, e.g. http:
        String sub = url.substring(url.indexOf(':') + 1);
        // extract host from Common Internet Scheme Syntax, e.g. http://
        if (sub.indexOf("//") != -1) {
            sub = sub.substring(sub.indexOf("//") + 2);
        }
        // first remove port, e.g. http://test.com:21
        if (sub.lastIndexOf(':') != -1) {
            sub = sub.substring(0, sub.lastIndexOf(':'));
        }
        // remove user and password, e.g. http://john:password@test.com
        sub = sub.substring(sub.indexOf(':') + 1);
        sub = sub.substring(sub.indexOf('@') + 1);
        // remove local parts, e.g. http://test.com/bla
        if (sub.indexOf('/') != -1) {
            sub = sub.substring(0, sub.indexOf('/'));
        }
        return sub;
    }

    /**
     * Checks if the given GeneralName is in the permitted set.
     * 
     * @param name
     *            The GeneralName
     * @throws PKIXNameConstraintValidatorException
     *             If the <code>name</code>
     */
    public void checkPermitted(GeneralName name)
            throws PKIXNameConstraintValidatorException {
        switch (name.getTagNo()) {
            case 1:
                checkPermittedEmail(permittedSubtreesEmail,
                        extractNameAsString(name));
                break;
            case 2:
                checkPermittedDNS(permittedSubtreesDNS, DERIA5String
                        .getInstance(name.getName()).getString());
                break;
            case 4:
                checkPermittedDN(ASN1Sequence.getInstance(name.getName()
                        .getDERObject()));
                break;
            case 6:
                checkPermittedURI(permittedSubtreesURI, DERIA5String
                        .getInstance(name.getName()).getString());
                break;
            case 7:
                byte[] ip = ASN1OctetString.getInstance(name.getName())
                        .getOctets();

                checkPermittedIP(permittedSubtreesIP, ip);
        }
    }

    /**
     * Check if the given GeneralName is contained in the excluded set.
     * 
     * @param name
     *            The GeneralName.
     * @throws PKIXNameConstraintValidatorException
     *             If the <code>name</code> is excluded.
     */
    public void checkExcluded(GeneralName name)
            throws PKIXNameConstraintValidatorException {
        switch (name.getTagNo()) {
            case 1:
                checkExcludedEmail(excludedSubtreesEmail,
                        extractNameAsString(name));
                break;
            case 2:
                checkExcludedDNS(excludedSubtreesDNS,
                        DERIA5String.getInstance(name.getName()).getString());
                break;
            case 4:
                checkExcludedDN(ASN1Sequence.getInstance(name.getName()
                        .getDERObject()));
                break;
            case 6:
                checkExcludedURI(excludedSubtreesURI,
                        DERIA5String.getInstance(name.getName()).getString());
                break;
            case 7:
                byte[] ip = ASN1OctetString.getInstance(name.getName())
                        .getOctets();

                checkExcludedIP(excludedSubtreesIP, ip);
        }
    }

    /**
     * Updates the permitted set of these name constraints with the intersection
     * with the given subtree.
     * 
     * @param permitted
     *            The permitted subtrees
     */

    public void intersectPermittedSubtree(ASN1Sequence permitted) {
        Map subtreesMap = new HashMap();

        // group in sets in a map ordered by tag no.
        for (Enumeration e = permitted.getObjects(); e.hasMoreElements();) {
            GeneralSubtree subtree = GeneralSubtree
                    .getInstance(e.nextElement());
            // BEGIN android-changed
            Integer tagNo = Integer.valueOf(subtree.getBase().getTagNo());
            // END android-changed
            if (subtreesMap.get(tagNo) == null) {
                subtreesMap.put(tagNo, new HashSet());
            }
            ((Set) subtreesMap.get(tagNo)).add(subtree);
        }

        for (Iterator it = subtreesMap.entrySet().iterator(); it.hasNext();) {
            Map.Entry entry = (Map.Entry) it.next();

            // go through all subtree groups
            switch (((Integer) entry.getKey()).intValue()) {
                case 1:
                    permittedSubtreesEmail = intersectEmail(
                            permittedSubtreesEmail, (Set) entry.getValue());
                    break;
                case 2:
                    permittedSubtreesDNS = intersectDNS(permittedSubtreesDNS,
                            (Set) entry.getValue());
                    break;
                case 4:
                    permittedSubtreesDN = intersectDN(permittedSubtreesDN,
                            (Set) entry.getValue());
                    break;
                case 6:
                    permittedSubtreesURI = intersectURI(permittedSubtreesURI,
                            (Set) entry.getValue());
                    break;
                case 7:
                    permittedSubtreesIP = intersectIP(permittedSubtreesIP,
                            (Set) entry.getValue());
            }
        }
    }

    private String extractNameAsString(GeneralName name) {
        return DERIA5String.getInstance(name.getName()).getString();
    }

    public void intersectEmptyPermittedSubtree(int nameType) {
        switch (nameType) {
            case 1:
                permittedSubtreesEmail = new HashSet();
                break;
            case 2:
                permittedSubtreesDNS = new HashSet();
                break;
            case 4:
                permittedSubtreesDN = new HashSet();
                break;
            case 6:
                permittedSubtreesURI = new HashSet();
                break;
            case 7:
                permittedSubtreesIP = new HashSet();
        }
    }

    /**
     * Adds a subtree to the excluded set of these name constraints.
     * 
     * @param subtree
     *            A subtree with an excluded GeneralName.
     */
    public void addExcludedSubtree(GeneralSubtree subtree) {
        GeneralName base = subtree.getBase();

        switch (base.getTagNo()) {
            case 1:
                excludedSubtreesEmail = unionEmail(excludedSubtreesEmail,
                        extractNameAsString(base));
                break;
            case 2:
                excludedSubtreesDNS = unionDNS(excludedSubtreesDNS,
                        extractNameAsString(base));
                break;
            case 4:
                excludedSubtreesDN = unionDN(excludedSubtreesDN,
                        (ASN1Sequence) base.getName().getDERObject());
                break;
            case 6:
                excludedSubtreesURI = unionURI(excludedSubtreesURI,
                        extractNameAsString(base));
                break;
            case 7:
                excludedSubtreesIP = unionIP(excludedSubtreesIP,
                        ASN1OctetString.getInstance(base.getName()).getOctets());
                break;
        }
    }

    /**
     * Returns the maximum IP address.
     * 
     * @param ip1
     *            The first IP address.
     * @param ip2
     *            The second IP address.
     * @return The maximum IP address.
     */
    private static byte[] max(byte[] ip1, byte[] ip2) {
        for (int i = 0; i < ip1.length; i++) {
            if ((ip1[i] & 0xFFFF) > (ip2[i] & 0xFFFF)) {
                return ip1;
            }
        }
        return ip2;
    }

    /**
     * Returns the minimum IP address.
     * 
     * @param ip1
     *            The first IP address.
     * @param ip2
     *            The second IP address.
     * @return The minimum IP address.
     */
    private static byte[] min(byte[] ip1, byte[] ip2) {
        for (int i = 0; i < ip1.length; i++) {
            if ((ip1[i] & 0xFFFF) < (ip2[i] & 0xFFFF)) {
                return ip1;
            }
        }
        return ip2;
    }

    /**
     * Compares IP address <code>ip1</code> with <code>ip2</code>. If ip1 is
     * equal to ip2 0 is returned. If ip1 is bigger 1 is returned, -1 otherwise.
     * 
     * @param ip1
     *            The first IP address.
     * @param ip2
     *            The second IP address.
     * @return 0 if ip1 is equal to ip2, 1 if ip1 is bigger, -1 otherwise.
     */
    private static int compareTo(byte[] ip1, byte[] ip2) {
        if (Arrays.areEqual(ip1, ip2)) {
            return 0;
        }
        if (Arrays.areEqual(max(ip1, ip2), ip1)) {
            return 1;
        }
        return -1;
    }

    /**
     * Returns the logical OR of the IP addresses <code>ip1</code> and
     * <code>ip2</code>.
     * 
     * @param ip1
     *            The first IP address.
     * @param ip2
     *            The second IP address.
     * @return The OR of <code>ip1</code> and <code>ip2</code>.
     */
    private static byte[] or(byte[] ip1, byte[] ip2) {
        byte[] temp = new byte[ip1.length];
        for (int i = 0; i < ip1.length; i++) {
            temp[i] = (byte) (ip1[i] | ip2[i]);
        }
        return temp;
    }

    public int hashCode() {
        return hashCollection(excludedSubtreesDN)
                + hashCollection(excludedSubtreesDNS)
                + hashCollection(excludedSubtreesEmail)
                + hashCollection(excludedSubtreesIP)
                + hashCollection(excludedSubtreesURI)
                + hashCollection(permittedSubtreesDN)
                + hashCollection(permittedSubtreesDNS)
                + hashCollection(permittedSubtreesEmail)
                + hashCollection(permittedSubtreesIP)
                + hashCollection(permittedSubtreesURI);
    }

    private int hashCollection(Collection coll) {
        if (coll == null) {
            return 0;
        }
        int hash = 0;
        Iterator it1 = coll.iterator();
        while (it1.hasNext()) {
            Object o = it1.next();
            if (o instanceof byte[]) {
                hash += Arrays.hashCode((byte[]) o);
            } else {
                hash += o.hashCode();
            }
        }
        return hash;
    }

    public boolean equals(Object o) {
        if (!(o instanceof PKIXNameConstraintValidator)) {
            return false;
        }
        PKIXNameConstraintValidator constraintValidator = (PKIXNameConstraintValidator) o;
        return collectionsAreEqual(constraintValidator.excludedSubtreesDN,
                excludedSubtreesDN)
                && collectionsAreEqual(constraintValidator.excludedSubtreesDNS,
                        excludedSubtreesDNS)
                && collectionsAreEqual(
                        constraintValidator.excludedSubtreesEmail,
                        excludedSubtreesEmail)
                && collectionsAreEqual(constraintValidator.excludedSubtreesIP,
                        excludedSubtreesIP)
                && collectionsAreEqual(constraintValidator.excludedSubtreesURI,
                        excludedSubtreesURI)
                && collectionsAreEqual(constraintValidator.permittedSubtreesDN,
                        permittedSubtreesDN)
                && collectionsAreEqual(
                        constraintValidator.permittedSubtreesDNS,
                        permittedSubtreesDNS)
                && collectionsAreEqual(
                        constraintValidator.permittedSubtreesEmail,
                        permittedSubtreesEmail)
                && collectionsAreEqual(constraintValidator.permittedSubtreesIP,
                        permittedSubtreesIP)
                && collectionsAreEqual(
                        constraintValidator.permittedSubtreesURI,
                        permittedSubtreesURI);
    }

    private boolean collectionsAreEqual(Collection coll1, Collection coll2) {
        if (coll1 == coll2) {
            return true;
        }
        if (coll1 == null || coll2 == null) {
            return false;
        }
        if (coll1.size() != coll2.size()) {
            return false;
        }
        Iterator it1 = coll1.iterator();

        while (it1.hasNext()) {
            Object a = it1.next();
            Iterator it2 = coll2.iterator();
            boolean found = false;
            while (it2.hasNext()) {
                Object b = it2.next();
                if (equals(a, b)) {
                    found = true;
                    break;
                }
            }
            if (!found) {
                return false;
            }
        }
        return true;
    }

    private boolean equals(Object o1, Object o2) {
        if (o1 == o2) {
            return true;
        }
        if (o1 == null || o2 == null) {
            return false;
        }
        if (o1 instanceof byte[] && o2 instanceof byte[]) {
            return Arrays.areEqual((byte[]) o1, (byte[]) o2);
        } else {
            return o1.equals(o2);
        }
    }

    /**
     * Stringifies an IPv4 or v6 address with subnet mask.
     * 
     * @param ip
     *            The IP with subnet mask.
     * @return The stringified IP address.
     */
    private String stringifyIP(byte[] ip) {
        String temp = "";
        for (int i = 0; i < ip.length / 2; i++) {
            temp += Integer.toString(ip[i] & 0x00FF) + ".";
        }
        temp = temp.substring(0, temp.length() - 1);
        temp += "/";
        for (int i = ip.length / 2; i < ip.length; i++) {
            temp += Integer.toString(ip[i] & 0x00FF) + ".";
        }
        temp = temp.substring(0, temp.length() - 1);
        return temp;
    }

    private String stringifyIPCollection(Set ips) {
        String temp = "";
        temp += "[";
        for (Iterator it = ips.iterator(); it.hasNext();) {
            temp += stringifyIP((byte[]) it.next()) + ",";
        }
        if (temp.length() > 1) {
            temp = temp.substring(0, temp.length() - 1);
        }
        temp += "]";
        return temp;
    }

    public String toString() {
        String temp = "";
        temp += "permitted:\n";
        if (permittedSubtreesDN != null) {
            temp += "DN:\n";
            temp += permittedSubtreesDN.toString() + "\n";
        }
        if (permittedSubtreesDNS != null) {
            temp += "DNS:\n";
            temp += permittedSubtreesDNS.toString() + "\n";
        }
        if (permittedSubtreesEmail != null) {
            temp += "Email:\n";
            temp += permittedSubtreesEmail.toString() + "\n";
        }
        if (permittedSubtreesURI != null) {
            temp += "URI:\n";
            temp += permittedSubtreesURI.toString() + "\n";
        }
        if (permittedSubtreesIP != null) {
            temp += "IP:\n";
            temp += stringifyIPCollection(permittedSubtreesIP) + "\n";
        }
        temp += "excluded:\n";
        if (!excludedSubtreesDN.isEmpty()) {
            temp += "DN:\n";
            temp += excludedSubtreesDN.toString() + "\n";
        }
        if (!excludedSubtreesDNS.isEmpty()) {
            temp += "DNS:\n";
            temp += excludedSubtreesDNS.toString() + "\n";
        }
        if (!excludedSubtreesEmail.isEmpty()) {
            temp += "Email:\n";
            temp += excludedSubtreesEmail.toString() + "\n";
        }
        if (!excludedSubtreesURI.isEmpty()) {
            temp += "URI:\n";
            temp += excludedSubtreesURI.toString() + "\n";
        }
        if (!excludedSubtreesIP.isEmpty()) {
            temp += "IP:\n";
            temp += stringifyIPCollection(excludedSubtreesIP) + "\n";
        }
        return temp;
    }
}
